Can you create a small HTML report with your display graph issue, zip the HTML files and create an issue (https://opencppcoverage.codeplex.com/workitem/list/basic) so that
you will be able to attached the zip file?
Can you also tell me your operating system, OpenCppCoverage version and attached the log file so that I can investigate?

Hi there, I have also got past this issue now (although worryingly I do not really know why it stopped happening).

The thing that was causing it for me was an old pdb file seemingly magically reappearing in the debug directory overwriting the newly produced one. I would assume this is more likely to be a compiler issue than an issue with OpenCppCoverage and unfortunately
I can not now reproduce the problem to create the requested output.